Louvers are openings in structures with slanting or sloping slats. They are commonly formed in parallel to create a grille member used to aesthetically conceal and protect an internal structure, excluding weather elements such as sun and rain while allowing ventilation. Typically, louvers are formed in sheet metal panels. The panels find application in the automotive, industrial, and electrical fields.
Machines for forming louvers are well known, as exemplified by U.S. Pat. No. 3,890,870 issued to Van Cleave on Jun. 24, 1975. The Van Cleave patent discloses a basic louver punch including a frame, a punch and die arrangement, and an actuating mechanism. The punch is forced through the sheet metal by reciprocating the punch vertically. One disadvantage of the punch-type mechanism is the risk of binding. Another disadvantage is the excess force necessary to operate the cutter to punch through the sheet metal. Such force requires machinery or at least a lever to assist the operator.
Another problem arises in prior art devices which include an indexing feature to permit louvers to be formed in series or in both longitudinal and transverse directions. Such indexing features fail to properly align the punch and die, which may cause the louver to be formed in an incorrect position.
Still another problem with prior art devices is the rapid wear on the working edge of the anvil. The anvil is subjected to repeated shearing stress each time the cutting member punches through the sheet metal against the anvil. After a certain number of punching operations, the working edge of the anvil wears out and the anvil must either be sharpened or replaced.
Known louver-forming machines are relatively large, heavy, and expensive devices designed to repeatedly form a louver of a specified length, width, and depth in a particular structural part. They are neither portable nor, in general, adjustable. In addition, the known machines tend to score, mar, or distort the sheet metal into which the louvers are formed.
To overcome the shortcomings of the known louver-forming machines, a news portables louver-forming tool is provided. An object of the present invention is to provide a tool which is light enough to be transported for, but is not restricted to, use on site on existing automobiles, covers, or panels requiring louvers. A related object is to provide a tool which can be easily mounted in a standard bench vice, on a standard motor stand, or to a stand constructed specifically for its use. Such versatility facilitates use of the tool both when the sheet metal can be brought to the tool and when the sheet metal cannot be moved easily.
Another object is to provide a tool which can slice and form louvers of adjustable length, width, depth, and final shape into sheet metal. A related object is to provide a tool which can form louvers in three-dimensional (non-flat) sheet metal having lips, creases, folds, and curves common to automotive, industrial, and electrical panels.
It is still another object of the present invention to provide a tool which is sufficiently simple in operation and inexpensive to be useful and available to the average layperson interested in forming louvers. An additional object is to provide a tool which, when forming a louver, minimizes scores, mars, and distortion of the sheet metal in which the louvers are formed. Yet another object of this invention is to reduce the number of work cycles of the tool necessary to slice and form the desired louver.